Switch power is used in data logging applications where power must be conserved. There are two separate implementations of this concept within the iSIC data logger.
Sensor Switch Power
Sensors plugged into SDL ports P1, T, and A or powered through pin 2 of an iSIC’s digital terminal strip are powered using switch power. This allows power to these ports to be removed when the iSIC is not recording data. In applications with limited power and sensors with high current draw, this is essential to allowing extended deployment.
There are two ways switch power can be enabled in an iChart project file.
1. During the initial Project Setup Device Wizard switch power can be enabled for individual sensors when they are added. This feature is typically defaulted to an appropriate value. However, in a situation where this value must be altered, the Show Details button must be selected in the “Smart Sensor Properties” dialog box. SW.A should be selected for the type and any duration can then be entered in seconds below.
Figure 1: Smart Sensor Properties Dialog
2. After the initial setup the switch power settings are accessed through the navigation panel on the left side of iChart. Right click on the sensor that is to be modified and select Property. Settings can then be adjusted as described above. Note that changing this value after initial setup will require the iSIC to be reprogrammed and result in a loss of any data currently stored on the device, so be sure to interrogate before proceeding.
Figure 2: Sensor Property Dialog
The duration is the amount of time prior to measurement that the instrument will receive power. Sensors vary in required warm-up time prior to a measurement being taken. Consult the device’s manual for further information regarding startup time.
REV: 13G18